Gearbox numbers and what they mean.

Greetings all

I was just starting a thread to get a definative answer as to what the gear box numbers corrispond to/ how strong various boxes are.

The main reason for this is later on I will be looking at forced induction and I was gauging how the drivetrain will hold up. From what I have read the number corrisponds to the strength of the box.

e.g. F17CR (found in the trusty berarri SRI) stands for 170 foot pounds of torque, close ratio (or some reports say it is actually measured in Nm). The only thing is there are people in europe running 260hp+ through this box with no modification other than in some cases a quaif LSD.

Has anyone boosted their opel and how has the gearbox held up to the extra ponies??

Quote:

Originally Posted by SilentShout

Greetings all

I was just starting a thread to get a definative answer as to what the gear box numbers corrispond to/ how strong various boxes are.

The main reason for this is later on I will be looking at forced induction and I was gauging how the drivetrain will hold up. From what I have read the number corrisponds to the strength of the box.

e.g. F17CR (found in the trusty berarri SRI) stands for 170 foot pounds of torque, close ratio (or some reports say it is actually measured in Nm). The only thing is there are people in europe running 260hp+ through this box with no modification other than in some cases a quaif LSD.

Has anyone boosted their opel and how has the gearbox held up to the extra ponies??

I don't believe the gearbox numbers 13,15,17, etc actually correspond to any given amount of torque it can handle. For example, F13 and F15 gearboxes are the same internally, they only differ in the fact the F15 uses larger and stronger CVs than the F13. F13 and F17 boxes use the same inner CVs I believe.

As for how much the Getrag boxes handle, they can handle a fair bit of power all depending on your clutch setup and more importantly, your launching technique. Having upwards of 300hp going through a F17 and repeatedly dumping the clutch isn't going to your gearbox any favours. I do remember @gman saying something like this in regards to a F23 gearbox that is usually found in the Astra SRi turbo and some other models with 2.0/2.2 engines (turbo and non-turbo boxes here differ slightly too I'm led to believe).

If you need a gearbox upgrade with the addition of forced induction, I would look into whether a F23 (would have to be from a Z20LET, C20SEL or C22SEL, these would have the Family II bellhousing pattern) could be fitted to the Z18XE, as I know some of the earlier F16/F18/F20 boxes (which were for the Family II engines) could be bolted to the Family 1 blocks. And the F23 box fits in a Corsa C with the gearbox mounts from the European Corsa C SRi 1.7CDTi diesel (which also uses the F23 box, albeit different bellhousing pattern). You'd need the matching shafts/CVs to fit, the shifter mechanism and cables from the SRi diesel. But then, if I were going to the hassle of turboing a Z18XE and needing to fit a F23, I'd just fit the matching Z20LET with it and ditch the Z18XE altogether.

Ah i thought the boxes were made by getrag :)

and Id like to keep the Close ratio for that maximum fun feel haha. although from what i can tell the ratios arent that drastically different from the standard F17 box.

Cheers for all your help with the different numbers, its exactily what I was looking for.

Also who said anything about a Turbo?? ;)